I regularly harvest pictures and content from the internet to include in
my messages to family and friends, or if I want to include them in my
documents. The content then turns up in the body of the e-mail/document.
With e-mail if the receiver allows HTML it will show in the body, if
they choose 'text only' then the content will be included as an attachment.

I do it this way: When I find something I want to share I highlight
those bits and right click to copy - just 'copy', I then open the mail
or document, select the insertion point and right click again selecting
'paste' - job done. Recently a lot of frames and stuff accompany a
copied internet content but there are 'tools' and methods to de clutter
this stuff.

If you are sending a previously received message and it's content why
not just forward it and edit the forwarded edition before sending.........